Overview: Ta₂Se₆

Structure info
Layer group	pmmn
Layer group number	46
Structure origin	original03-18

Stability
Energy above convex hull [eV/atom]	0.046
Heat of formation [eV/atom]	-0.634
Dynamically stable	Yes

Basic properties
Magnetic	No
Band gap (PBE) [eV]	0.000

Repeat: 1234   Download: XYZ CIF JSON

Axis	x [Å]	y [Å]	z [Å]	Periodic
1	5.385	-0.000	0.000	Yes
2	0.000	3.496	0.000	Yes
3	-0.000	0.000	21.188	No

Lengths [Å]	5.385	3.496	21.188
Angles [°]	90.000	90.000	90.000

Crystal structure

Symmetries
2D Bravais type	Rectangular (op)
Layer group number	46
Layer group	pmmn
Space group number (bulk in AA-stacking)	59
Space group (bulk in AA-stacking)	Pmmn
Point group	mmm
Inversion symmetry	Yes

Structure data
Formula	Ta2Se6
Stoichiometry	AB3
Number of atoms	8
Unit cell area [Å2]	18.827
Thickness [Å]	6.102

Stability

Convex hull

Ta2Se6 (2TaSe3-1)
Heat of formation [eV/atom]	-0.63
Energy above convex hull [eV/atom]	0.05

Monolayers from C2DB
TaSe2 (1TaSe2-1)	-0.84 eV/atom
TaSe2 (1TaSe2-2)	-0.81 eV/atom
Ta4Se6 (2Ta2Se3-1)	-0.79 eV/atom
Ta7Se12 (1Ta7Se12-1)	-0.77 eV/atom
Ta4Se12 (4TaSe3-1)	-0.68 eV/atom
Ta8Se12 (4Ta2Se3-1)	-0.66 eV/atom
Ta2Se6, (2TaSe3-1)	-0.63 eV/atom
Ta9Se12 (3Ta3Se4-1)	-0.56 eV/atom
Se2Ta4 (2SeTa2-1)	-0.49 eV/atom
Se2Ta2 (2SeTa-1)	-0.38 eV/atom
TaSe2 (1TaSe2-3)	-0.37 eV/atom
Se2Ta2 (2SeTa-2)	-0.34 eV/atom
Se2Ta2 (2SeTa-3)	-0.30 eV/atom
Se2Ta2 (2SeTa-4)	-0.13 eV/atom
Se2Ta2 (2SeTa-5)	-0.12 eV/atom
Se2 (2Se-1)	0.21 eV/atom
Se2 (2Se-2)	0.29 eV/atom

Bulk crystals from OQMD123
Se2Ta	-0.84 eV/atom
Se12Ta4	-0.68 eV/atom
Se2Ta4	-0.46 eV/atom
Se3	0.00 eV/atom
Ta	0.00 eV/atom

Phonons

Minimum eigenvalue of Hessian [eV/Ų]

-0.00

Linear deformations

Stiffness tensor

Cij (N/m)	xx	yy	xy
xx	139.05	17.16	-0.00
yy	16.76	143.78	-0.00
xy	0.00	0.00	62.80

Stiffness tensor eigenvalues
Eigenvalue 0	62.80 N/m
Eigenvalue 1	124.29 N/m
Eigenvalue 2	158.54 N/m

Electronic bands

Band structure and DOS

Key values [eV]
Band gap (PBE)	0.000
Direct band gap (PBE)	0.000
Fermi level wrt. vacuum (PBE)	-4.588

Fermi surface

Electronic properties

Bader charges

Atom No.	Chemical symbol	Charges [|e|]
0	Ta	1.67
1	Ta	1.67
2	Se	-0.75
3	Se	-0.75
4	Se	-0.46
5	Se	-0.46
6	Se	-0.46
7	Se	-0.46

Optical properties

Optical polarizability

Properties
Interband polarizability (x) [Å]	13.374
Interband polarizability (y) [Å]	11.651
Interband polarizability (z) [Å]	0.628
Plasma frequency (x) [eV Å0.5]	6.463
Plasma frequency (y) [eV Å0.5]	16.419

Raman spectrum

Mode	Frequency (1/cm)	Degeneracy
Mode 1	0.1	3
Mode 2	36.1	1
Mode 3	66.5	1
Mode 4	92.5	3
Mode 5	129.8	1
Mode 6	137.9	1
Mode 7	145.8	2
Mode 8	148.6	1
Mode 9	152.8	2
Mode 10	181.6	1
Mode 11	190.9	1
Mode 12	194.6	1
Mode 13	207.8	1
Mode 14	212.6	2
Mode 15	229.9	1
Mode 16	268.8	2

Miscellaneous

Miscellaneous details
Unique ID	2TaSe3-1
Number of atoms	8
Number of species	2
Formula	Ta2Se6
Reduced formula	TaSe3
Stoichiometry	AB3
Unit cell area [Å2]	18.827
Original file-system folder	/home/niflheim2/cmr/C2DB-ASR/tree/AB3/TaSe3/Ta2Se6-f9ab1865cb8c
Old uid	Ta2Se6-f9ab1865cb8c
Space group (bulk in AA-stacking)	Pmmn
Space group number (bulk in AA-stacking)	59
Point group	mmm
Inversion symmetry	Yes
Layer group number	46
Layer group	pmmn
2D Bravais type	Rectangular (op)
Thickness [Å]	6.102
Structure origin	original03-18
Band gap (PBE) [eV]	0.000

Miscellaneous details
Direct band gap (PBE) [eV]	0.000
gap_dir_nosoc	0.000
Vacuum level [eV]	5.550
Fermi level wrt. vacuum (PBE) [eV]	-4.588
minhessianeig	-0.000
Dynamically stable	Yes
Interband polarizability (x) [Å]	13.374
Interband polarizability (y) [Å]	11.651
Interband polarizability (z) [Å]	0.628
Plasma frequency (x) [eV Å0.5]	6.463
Plasma frequency (y) [eV Å0.5]	16.419
Energy [eV]	-45.601
Magnetic	No
Spin axis	z
Magnetic anisotropy energy, xz [meV/unit cell]	0.000
Magnetic anisotropy energy, yz [meV/unit cell]	0.000
Energy above convex hull [eV/atom]	0.046
Heat of formation [eV/atom]	-0.634